Because radio waves in the shortwave band can be reflected or refracted from the ionosphere.Therefore, short waves directed at an angle into the sky can be reflected back to Earth at great distances, beyond the horizon.

Due to the refraction of sound, we can hear sounds easily at night than during clear days.

On a clear day, the lower layer of the atmosphere is hotter than the layers above. Since sound travels faster in a hotter medium, its speed is greater near the surface. As a result, the waves are bent away from the surface. Thus, the intensity of the sound waves diminishes and does not seem to travel a long distance. On a clear night, the lower layer of the atmosphere is colder than the air above. Now,...

The differences between transverse and longitudinal waves are as listed below:

Transverse waves	Longitudinal waves
The particles of the medium vibrate in the direction perpendicular to the direction of wave propagation.	The particles of the medium vibrateparallel to the direction of wavepropagation.
Alternate crests and trough areformed.	Alternate compression and rarefactionof the medium are formed.
These are formed in solids and overliquid surfaces.	These are formed in...

The differences between progressive waves and stationary waves are as listed below:

Progressive waves	Stationary waves
The disturbance travels forward.	The disturbances are confined to aparticular region.
The amplitude of vibration ofeach particle is same.	The amplitude is zero at nodes and goeson increasing to become maximum at antinodes.
Energy is transferred forwardalong the waves.	No transfer of energy is in the medium.
No particles in the medium are atrest.	...

Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that’s why it is more energetic than long waves. Shortwave radio is radio communication using the upper MF (medium frequency) and all of the HF (high frequency) portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are...

When Mercury is poured into the glass it forms many number of spherical droplets. This is due to the dominance of cohesive force on adhesive force. or we can say adhesive force is negligibly small.

Cohesion-it is the property of a substance to stick with its own kind, adhesion on the other hand is the property of a substance to stick with or gather with substance other than its own kind. And respectively the forces are cohesive and adhesive force.

A basic approach would be to use the definition of oscillation. One oscillation of Kinetic energy occurs when it reaches minimum(extreme position) from maximum( equilibrium position) and then to minimum. This process occurs twice in one oscillation of the particle, so the frequency at which the kinetic energy would oscillates is twice than that of the particle which is 2f.

The distance between nodes referred to in the problem means that that
λ/2=3.84cm, or
λ=0.077m. Therefore, the frequency is

f=v/λ=(1520m/s)/(0.077m)19740.25
Hz

The energy carried by the water waves comes from kinetic energy of stone hitting the water surface.

No, an oscillation is not a wave. The term wave implies the transfer of energy through successive vibrations of the particles of the medium. Hence, the oscillations of the body do not make up a wave.

Sound needs a material medium for its propagation from one place to another place. So sound cannot travel through vacuum. Since there is a vacuum between the planets and the earth, so the sound of explosions taking place on other planets cannot pass through this vacuum.

The type of wave that propagates in a liquid is called a mechanical wave. Mechanical waves are waves that require a medium to propagate, meaning they need a substance to travel through. In the case of liquid, such as water, mechanical waves can travel through it.

There are two primary types of mechanical waves that can propagate in a liquid: transverse waves and longitudinal waves.

1. Transverse Waves: In a transverse wave, the particles of the medium move perpendicular to the direction of wave...